The false positive and false negative results are summarized by schedule in a data table. The green line on the chart describes the analyte reporting level.
The false positive and false negative chart display all concentration results, and false positives are represented by a red asterisk and false negatives are
represented by a red down arrow.
A list of false positives and false negatives below the chart summarizes the false positive and false negative results and provides expected concentration and result
concentrations for every analyte for every schedule OBSP assesses.
A false positive result - when an analyte is reported by the laboratory when it is not present in the sample. False positives can result from random variability in background
response, contamination, degradation of a parent product or misidentification of the analyte.
A false negative result - the analyte is present in the sample but it is not reported by the laboratory. False negatives can arise from random variability, lower than normally expected
recovery, or misidentification of the analyte.
Note: If an analyte of interest is not seen in the method listing, there is no OBSP data available for that analyte
Charts and data secured from this U.S. Geological Survey (USGS) web page (identified as "OBSP") have not received official USGS approval and as such are provisional and subject to revision. The charts and data are released on the condition that neither the USGS nor the U.S. Government shall be held liable for any damages resulting from its authorized or unauthorized use.
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U.S. Geological Survey
